import Vue from 'vue';

/*

*  转载：https://blog.csdn.net/qq_35035975/article/details/112648483?utm_medium=distribute.pc_relevant.none-task-blog-baidujs_title-0&spm=1001.2101.3001.4242

*  使用方法

*  将以下代码复制到一个js文件中，然后在入口文件main.js中import引入即可；

*  给elementUI的dialog上加上 v-dialogDrag 指令就可以实现弹窗的全屏和拉伸了。

*  给dialog设置 :close-on-click-modal="false" , 禁止点击遮罩层关闭弹出层

*  如果是form表单，不要将提交等按钮放置el-form-item，以免在上下拉伸时被隐藏

*/

/*

*  具体功能

*  1. 弹窗拖拽

*  2. 双击弹窗头部全屏

*  3. 水平方向拉伸

*/

// v-dialogDrag: 弹窗拖拽+水平方向伸缩

Vue.directive('dialogDrag', {

    bind(el, binding, vnode, oldVnode) {

        //弹框可拉伸最小宽高

        let minWidth = 400;

        let minHeight = 300;

        //初始非全屏

        let isFullScreen = false;

        //当前宽高

        let nowWidth = 0;

        let nowHight = 0;

        //当前顶部高度

        let nowMarginTop = 0;

        //获取弹框头部（这部分可双击全屏）

        const dialogHeaderEl = el.querySelector('.el-dialog__header');

        //弹窗

        const dragDom = el.querySelector('.el-dialog');

        //给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；

        dragDom.style.overflow = "auto";

        //清除选择头部文字效果

        //dialogHeaderEl.onselectstart = new Function("return false");

        //头部加上可拖动cursor

        dialogHeaderEl.style.cursor = 'move';

        // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);

        const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);

        let moveDown = (e) => {

            // 鼠标按下，计算当前元素距离可视区的距离

            const disX = e.clientX - dialogHeaderEl.offsetLeft;

            const disY = e.clientY - dialogHeaderEl.offsetTop;

            // 获取到的值带px 正则匹配替换

            let styL, styT;

            // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px

            if (sty.left.includes('%')) {

                styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);

                styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);

            } else {

                styL = +sty.left.replace(/\px/g, '');

                styT = +sty.top.replace(/\px/g, '');

            };

            document.onmousemove = function (e) {

                // 通过事件委托，计算移动的距离

                const l = e.clientX - disX;

                const t = e.clientY - disY;

                // 移动当前元素 

                dragDom.style.left = `${l + styL}px`;

                dragDom.style.top = `${t + styT}px`;

                //将此时的位置传出去

                //binding.value({x:e.pageX,y:e.pageY})

            };

            document.onmouseup = function (e) {

                document.onmousemove = null;

                document.onmouseup = null;

            };

        }

        dialogHeaderEl.onmousedown = moveDown;

        //双击头部全屏效果

        dialogHeaderEl.ondblclick = (e) => {

            if (isFullScreen == false) {

                nowHight = dragDom.clientHeight;

                nowWidth = dragDom.clientWidth;

                nowMarginTop = dragDom.style.marginTop;

                dragDom.style.left = 0;

                dragDom.style.top = 0;

                dragDom.style.height = "100VH";

                dragDom.style.width = "100VW";

                dragDom.style.marginTop = 0;

                isFullScreen = true;

                dialogHeaderEl.style.cursor = 'initial';

                dialogHeaderEl.onmousedown = null;

            } else {

                dragDom.style.height = "auto";

                dragDom.style.width = nowWidth + 'px';

                dragDom.style.marginTop = nowMarginTop;

                isFullScreen = false;

                dialogHeaderEl.style.cursor = 'move';

                dialogHeaderEl.onmousedown = moveDown;

            }

        }

        dragDom.onmousemove = function (e) {

            let moveE = e;

            if (e.clientX > dragDom.offsetLeft + dragDom.clientWidth - 10 || dragDom.offsetLeft + 10 > e.clientX) {

                dragDom.style.cursor = 'w-resize';

            } else if (el.scrollTop + e.clientY > dragDom.offsetTop + dragDom.clientHeight - 10) {

                dragDom.style.cursor = 's-resize';

            } else {

                dragDom.style.cursor = 'default';

                dragDom.onmousedown = null;

            }

            dragDom.onmousedown = (e) => {

                const clientX = e.clientX;

                const clientY = e.clientY;

                let elW = dragDom.clientWidth;

                let elH = dragDom.clientHeight;

                let EloffsetLeft = dragDom.offsetLeft;

                let EloffsetTop = dragDom.offsetTop;

                dragDom.style.userSelect = 'none';

                let ELscrollTop = el.scrollTop;

                //判断点击的位置是不是为头部

                if (clientX > EloffsetLeft && clientX < EloffsetLeft + elW && clientY > EloffsetTop && clientY < EloffsetTop + 100) {

                    //如果是头部在此就不做任何动作，以上有绑定dialogHeaderEl.onmousedown = moveDown;

                }else{

                    document.onmousemove = function (e) {

                        e.preventDefault(); // 移动时禁用默认事件

                        //左侧鼠标拖拽位置

                        if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {

                            //往左拖拽

                            if (clientX > e.clientX) {

                                dragDom.style.width = elW + (clientX - e.clientX) * 2 + 'px';

                            }

                            //往右拖拽

                            if (clientX < e.clientX) {

                                if(dragDom.clientWidth < minWidth){

                                }else{

                                    dragDom.style.width = elW - (e.clientX - clientX) * 2 + 'px';

                                }

                            }

                        }

                        //右侧鼠标拖拽位置

                        if (clientX > EloffsetLeft + elW - 10 && clientX < EloffsetLeft + elW) {

                            //往左拖拽

                            if (clientX > e.clientX) {

                                if (dragDom.clientWidth < minWidth) {

                                } else {

                                    dragDom.style.width = elW - (clientX - e.clientX) * 2 + 'px';

                                }

                            }

                            //往右拖拽

                            if (clientX < e.clientX) {

                                dragDom.style.width = elW + (e.clientX - clientX) * 2 + 'px';

                            }

                        }

                        //底部鼠标拖拽位置

                        if (ELscrollTop + clientY > EloffsetTop + elH - 20 && ELscrollTop + clientY < EloffsetTop + elH) {

                            //往上拖拽

                            if (clientY > e.clientY) {

                                if (dragDom.clientHeight < minHeight) {

                                } else {

                                    dragDom.style.height = elH - (clientY - e.clientY) * 2 + 'px';

                                }

                            }

                            //往下拖拽

                            if (clientY < e.clientY) {

                                dragDom.style.height = elH + (e.clientY - clientY) * 2 + 'px';

                            }

                        }

                    };

                    //拉伸结束

                    document.onmouseup = function (e) {

                        document.onmousemove = null;

                        document.onmouseup = null;

                    };

                }

            }

        }

    }

})

// 兼容ie,谷歌
// v-dialogDrags: 弹窗拖拽属性 （重点！！！ 给模态框添加这个属性模态框就能拖拽了）
Vue.directive('dialogDrags', { //属性名称dialogDrags，前面加v- 使用
    bind(el, binding, vnode, oldVnode) {
      const dialogHeaderEl = el.querySelector('.el-dialog__header');
      const dragDom = el.querySelector('.el-dialog');
      //dialogHeaderEl.style.cursor = 'move';
      dialogHeaderEl.style.cssText += ';cursor:move;'
      dragDom.style.cssText += ';top:0px;'
      dragDom.style.cssText += ';left:0px;'
  
      // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
      const sty = (function() {
        if (window.document.currentStyle) {
          return (dom, attr) => dom.currentStyle[attr];
        } else{
          return (dom, attr) => getComputedStyle(dom, false)[attr];
        }
      })()
  
      dialogHeaderEl.onmousedown = (e) => {
        // 鼠标按下，计算当前元素距离可视区的距离
        const disX = e.clientX - dialogHeaderEl.offsetLeft;
        const disY = e.clientY - dialogHeaderEl.offsetTop;
  
        const screenWidth = document.body.clientWidth; // body当前宽度
        const screenHeight = document.documentElement.clientHeight; // 可见区域高度(应为body高度，可某些环境下无法获取)
  
        const dragDomWidth = dragDom.offsetWidth; // 对话框宽度
        const dragDomheight = dragDom.offsetHeight; // 对话框高度
  
        const minDragDomLeft = dragDom.offsetLeft;
        const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth;
  
        const minDragDomTop = dragDom.offsetTop;
        const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomheight;
  
  
        // 获取到的值带px 正则匹配替换
        let styL = sty(dragDom, 'left');
        let styT = sty(dragDom, 'top');
  
        // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
        if(styL.includes('%')) {
          styL = +document.body.clientWidth * (+styL.replace(/\%/g, '') / 100);
          styT = +document.body.clientHeight * (+styT.replace(/\%/g, '') / 100);
        }else {
          styL = +styL.replace(/\px/g, '');
          styT = +styT.replace(/\px/g, '');
        };
  
        document.onmousemove = function (e) {
          // 通过事件委托，计算移动的距离
          let left = e.clientX - disX;
          let top = e.clientY - disY;
  
          // 边界处理
          if (-(left) > minDragDomLeft) {
            left = -(minDragDomLeft);
          } else if (left > maxDragDomLeft) {
            left = maxDragDomLeft;
          }
  
          if (-(top) > minDragDomTop) {
            top = -(minDragDomTop);
          } else if (top > maxDragDomTop) {
            top = maxDragDomTop;
          }
  
          // 移动当前元素
          dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`;
        };
  
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }
    }
  })